Methods and apparatus for preventing fraud in payment processing transactions

ABSTRACT

A method includes receiving an authorization request for a purchase transaction, and determining whether the authorization request arose from proximity-reading a proximity payment device. The method further includes mapping a first account number included in the authorization request into a second account number associated with the first account number if it is determined that the authorization request arose from proximity-reading a proximity payment device and if the first account number is qualified for mapping. In addition, the method includes transmitting the authorization request to an issuer financial institution with the second account number substituted for the first account number in the authorization request.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional application of prior co-pending application Ser.No. 11/952,334, filed Dec. 7, 2007 which claimed benefits to U.S.Provisional Application Ser. No. 60/942,073 filed Jun. 5, 2007, all ofwhich are incorporated herein by reference.

BACKGROUND

Proximity payment devices and systems are becoming increasingly popular.One such system is the “PayPass” system operated by MasterCardInternational Incorporated, which is the assignee hereof. MasterCardissuers now have the option of issuing PayPass payment devices to theircardholders. Some proximity payment devices (including proximity paymentdevices issued in the PayPass system) may have both a magnetic stripe(such as is provided on conventional credit or debit cards) as well as adata storage device or chipset (also referred to as a radio frequencyidentification or “RFID” chip) and an antenna to which the storagedevice is coupled. Both the RFID chip and the antenna may be embedded inthe body of the proximity payment device. The body of the proximitypayment device may have the same shape and dimensions as a conventionalpayment card such as a credit card or a debit card.

The RFID chip may store an account number to be wirelessly transmittedfrom the proximity payment device (via the antenna) when the paymentdevice is presented for proximity coupling to a point-of-sale terminal.

Further, proximity payment devices of the type described above may beused in conjunction with conventional point-of-sale terminals (or inmail order or telephone transactions or other non-face to facetransactions) where an account number stored in a magnetic stripe, orembossed or printed on a face of the payment device, is read andtransmitted for use in a transaction.

That is, some proximity payment devices may be used in proximity orwireless transactions as well as in standard payment card transactions.A proximity payment device may be manufactured in a variety of formfactors, including as a conventional-sized payment card or as a fob,keyring, wristband, or the like. These proximity payment devices haveenjoyed great success recently. Often, when the proximity payment deviceis not in the form factor of a conventional payment card, the proximitypayment device (e.g., a fob or wristband) may not include a magneticstripe and so is intended to be used only for transactions in whichproximity coupling is used to read the account number from the RFID chipin the proximity payment device.

Applicants have recognized a need to provide enhanced security forproximity payment devices. One issue that applicants have addressed isthe potential for proximity payment devices to be read by unauthorizedpersons who have the intention of collecting account number forfraudulent purposes.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of some embodiments of the present invention,and the manner in which the same are accomplished, will become morereadily apparent upon consideration of the following detaileddescription of the invention taken in conjunction with the accompanyingdrawings, which illustrate preferred and exemplary embodiments and whichare not necessarily drawn to scale, wherein:

FIG. 1 is a flow chart that illustrates, at a high level, an anti-fraudstrategy that is an aspect of the present invention.

FIG. 2 is a block diagram that illustrates a payment card transactionprocessing system provided according to some embodiments.

FIG. 3 is a block diagram that illustrates a computer that may beoperated by a payment card association in connection with the system ofFIG. 2.

FIG. 4 is a flow chart that illustrates a process that may be performedby the computer of FIG. 3.

FIG. 5 is a flow chart that illustrates a further process that may beperformed by the computer of FIG. 3.

FIG. 6 is a block diagram that illustrates a system that is operable inconnection with the present invention to allow payment card holders toapply for issuance of proximity payment devices.

FIG. 7 is a block diagram representation of a computer that may beoperated by a payment card association in the system of FIG. 6 inconnection with certain aspects of the invention.

FIG. 8 is a flow chart that illustrates a process that may be performedby the computer of FIG. 7.

FIG. 9 is a block diagram representation of a computer system that maybe operated by a payment card association in the system of FIG. 2 inconnection with still other aspects of the invention.

FIG. 10 is a flow chart that illustrates a process that may be performedby the computer system of FIG. 9 in accordance with aspects of theinvention.

FIG. 11 is a block diagram representation of a payment card transactionprocessing system, schematically representing a circumstance when a cardissuer's host computer is not available to handle transactions.

FIG. 12 is a flow chart that illustrates a process that may be performedin accordance with aspects of the invention by a computer systemoperated by a payment card association in connection with the system ofFIG. 11.

FIG. 13 is a flow chart that illustrates certain details of the processof FIG. 12.

DETAILED DESCRIPTION

In general, and for the purpose of introducing concepts of embodimentsof the present invention, a payment card system may be organized so thataccount numbers that are available for reading by proximitycommunication from proximity payment devices are not accepted forpayment card system transactions unless such account numbers are enteredinto the system via a proximity reader that is part of a point of saleterminal. In other words, a special class of account numbers is createdthat are assigned only to proximity payment devices and that are notstored on the magnetic stripes of magnetic stripe payment cards. Eachaccount number that is issued from this special class of account numbersis associated with a so-called “primary account number” or “PAN”. ThePANs are used to identify actual payment card accounts and may be storedon the magnetic stripes of payment cards in a conventional manner. Whenan account number from the special class of account numbers (hereinafterreferred to as “proximity-device-only account numbers”) is properly readby proximity reading at a point of sale terminal, theproximity-device-only account number is included in a transactionauthorization request initiated by the POS terminal. The payment system,and particularly a computer operated by the payment card association(e.g., MasterCard International Inc.), looks up the PAN with which theproximity-device-only account number is associated and substitutes theassociated PAN for the proximity-device-only account number whileforwarding the authorization request on to the issuer of the proximitypayment device.

However, in the event that the authorization request received by thepayment card association computer does not indicate that the transactionarose from proximity-reading a proximity payment device at a POSterminal, then the payment card association computer does not translatethe proximity-device-only account number into the associated PAN.Instead, an error message is generated and the authorization request isdeclined.

With this mode of handling transactions involving proximity-device-onlyaccount numbers, such account numbers will be accepted only intransactions in which they are properly read from proximity paymentdevices. Consequently, if a wrongdoer improperly obtains aproximity-device-only account number and attempts to use it in an onlinepurchase, or a telephone purchase, or by mail order, or by writing theproximity-device-only account number proximity-device-only accountnumber into the magnetic stripe of a counterfeit payment card and thenpresenting the counterfeit card at a POS terminal, all of theseattempted fraudulent transactions are likely to fail because theresulting authorization requests would be declined.

It should be noted that while creation of counterfeit magnetic stripepayment cards is known to be within the capabilities of some wrongdoers,it is much more difficult, and likely beyond the capabilities of most ifnot all wrongdoers, to create counterfeit proximity payment devicesincluding the required microelectronic components (RFID chips) and thento store misappropriated account numbers in the RFID chips.

Thus the above-mentioned special class of proximity-device-only accountnumbers, and the transaction handling regime described above (and infurther detail below) may provide a strong barrier against fraudulenttransactions arising from unauthorized reading of proximity paymentdevices.

Additional security may be provided by utilization of a dynamic securitycode that uses cryptographic techniques to confirm the validity ofproximity payment devices.

Another advantage provided by many or all of the embodiments describedherein is that the security features provided according to the inventionmay require little or no modification of the transaction processingsystems currently installed and in use by acquirer and issuer financialinstitutions. (As is well-known to those who are skilled in the art, an“acquirer” financial institution is one which has a banking relationshipwith the merchant that initiates the purchase transaction. Thus theacquirer (or a service provider acting on the acquirer's behalf)forwards authorization requests to the payment card association forrouting to the issuer financial institutions. The “issuer” is thefinancial institution that issued the payment card/proximity paymentdevice presented by the customer (or issued the account identified bythe account number submitted online or over the phone). Thus the issuer(or a service provider acting on the acquirer's behalf) may refer to thestatus of the customer's payment card account to determine whether toapprove or decline the authorization request.)

FIG. 1 is a flow chart that illustrates, at a high level, an anti-fraudstrategy that is an aspect of the present invention.

At 102 in FIG. 1, a payment card association and/or one or more of itsmember payment card issuers define one or more ranges of account numbersthat are to be assigned as primary account numbers (PANs) for paymentcard accounts. In accordance with conventional practices, the leadingdigits of the PAN ranges correspond to bank identification numbers(BINs) that identify the issuing financial institutions for the paymentcard accounts.

At 104 in FIG. 1, the payment card association and/or one or more of itsmember payment card issuers define one or more ranges of account numbersthat are to be used exclusively in proximity-read purchase transactions,and thus are to be loaded into the RFID chips of proximity paymentdevices. As noted above, these special account numbers may be referredto as “proximity-device-only account numbers”. When issued, eachproximity-device-only account number is associated with a previouslyissued PAN.

At 106 in FIG. 1, issuer financial institutions, and/or the payment cardassociation acting on behalf of an issuer financial institution, causesproximity-device-only account numbers to be loaded into proximitypayment devices to be issued to holders of the payment card accountsidentified by the PANs with which the proximity-device-only accountnumbers are associated. For example, a proximity-device-only accountnumber may be loaded into the RFID chip of a payment card, while theassociated PAN is stored on the magnetic stripe on the card and isembossed on the face of the card. Alternatively, theproximity-device-only account number may be loaded into the RFID chip ofa proximity payment device that is not card-shaped (e.g., a fob orwristband), and the proximity payment device may then be mailed to anaccount holder who already has a magnetic stripe payment card thatcarries the PAN associated with the proximity-device-only accountnumber. More details of one example process for issuing proximitypayment devices will be described below.

At 108, the payment card system operates such that transactions aredeclined in cases in which a proximity-device-only account number issubmitted to pay for the transaction but the transaction was notinitiated by proximity-reading a proximity payment device. As notedabove, this step enforces a measure that would prevent misappropriatedproximity-device-only account numbers from being fraudulently tenderedfor mag-stripe transactions, internet orders, phone orders, etc.

At 110, the payment card system operates such that, for transactionsinitiated by proximity-reading a proximity payment device to receive aproximity-device-only account number, the system or the issuer financialinstitution translates the proximity-device-only account numberinitially included in the authorization request into its associated PANand then proceeds to process the transaction as if the PAN had beentendered for the transaction.

FIG. 2 is a block diagram that illustrates a payment card transactionprocessing system 200 provided according to some embodiments.

Reference numeral 202 indicates a proximity payment device, which ispresented for reading by a point of sale terminal 204 to initiate apurchase transaction in the payment card transaction processing system200. Both the proximity payment device 202 and the POS terminal 204 maybe considered to be part of the payment card transaction processingsystem 200. The proximity payment device 202 may, for example, have anRFID chip (not separately shown) coupled to an antenna (not separatelyshown). A proximity-device-only account number may be stored in the RFIDchip and may be transmitted to the POS terminal in response to aninterrogation signal from the POS terminal. This may occur, for example,and in accordance with conventional practices, when the proximitypayment device is tapped on a proximity reader component (not separatelyshown) that is part of, or associated with, the POS terminal 204. Insome embodiments, the proximity payment device is shaped as a fob orwristband or has another convenient, non-card-shaped form factor. Inother embodiments, the proximity payment device has the shape and size(and appearance) of a conventional payment card. In the latter case, theproximity payment device may have a magnetic stripe and a PAN stored inthe magnetic stripe to allow the device also to be read by “swiping”through a standard magnetic stripe reader. The PAN stored in the magstripe is the one with which the proximity-device-only account numberstored in the RFID chip is associated. Thus, the PAN is stored in themag stripe, and the different but associated proximity-device-onlyaccount number is stored in the RFID chip on the card. In accordancewith conventional practice, the PAN may also be embossed on the face ofthe card, for use, e.g., in internet, mail or phone orders.

The POS terminal is in data communication, directly or indirectly, andat least from time to time, with a host computer 206 that is part of thepayment card transaction processing system 200 and is operated for or onbehalf of the acquirer financial institution which handles payment cardtransactions for the merchant which operates the POS terminal. Both theacquirer host computer 206 and the POS terminal 204 may be constitutedand may operate in a conventional manner.

Reference numeral 208 indicates an access point. The access point 208 isa conventional device via which the acquirer host computer is able toexchange data messages with a payment system computer 210 that is acentral component in the payment card transaction processing system 200.In accordance with conventional practices, the payment system computermay be operated by or on behalf of a payment card association (of whicha prominent example is MasterCard International Inc., the assigneehereof) and provides the central switching and message routing functionsamong the member financial institutions of the payment card association.Further details of the payment system computer 200 will be providedbelow, including aspects of the payment system computer that areprovided in accordance with aspects of the present invention.

The payment card transaction processing system 200 also includes anissuer host computer 212, and an access point 214 via which the issuerhost computer 212 exchanges data messages with the payment systemcomputer 210.

Although only one proximity payment device, one POS terminal, oneacquirer host computer, one issuer host computer and two access pointsare shown in the drawing, it should be understood that in practice thepayment card transaction processing system 200 may include a largenumber of proximity payment devices, POS terminals, acquirer hostcomputers, issuer host computers, and access points. In particular, thedrawing only shows components that are active in connection with asingle transaction out of a large number of transactions that may behandled by the payment card transaction processing system 200 on anongoing basis. Of course, the payment card transaction processing system200 may also include payment cards that are not proximity paymentdevices.

In some embodiments, all of the components of the payment cardtransaction processing system 200 may be entirely or substantiallyconventional, except that the payment system computer 210 may store dataand may be programmed to perform functions in accordance with aspects ofthe present invention. The proximity payment device 202 may also beconventional in its operation and structure. However, the proximitypayment device may store in its RFID chip a proximity-device-onlyaccount number, and if the proximity payment device is also a mag stripcard, the mag stripe may store a PAN that is associated with butdifferent from the proximity-device-only account number stored in theRFID chip.

In general the acquirer host computer 206 performs its conventionalfunctions of receiving authorization requests from POS terminals,forwarding the authorization requests through the payment cardtransaction processing system, receiving authorization responses, andrelaying the authorization responses to the POS terminals. Moreover, theissuer host computer 212 may in general perform its conventionalfunction of receiving authorization requests from the payment systemcomputer 210 and transmitting authorization responses back to thepayment system computer 210 with respect to the authorization requests.

FIG. 3 is a block diagram that illustrates details of the payment systemcomputer 210 shown in FIG. 2. The payment system computer 210 may beconventional in its hardware aspects but may be controlled by softwareand may store data to allow it to operate in accordance with aspects ofthe present invention.

Referring, then, to FIG. 3, the payment system computer 210 may includea computer processor 300 operatively coupled to a communication device301, a storage device 304, an input device 306 and an output device 308.

The computer processor 300 may be constituted by one or moreconventional processors. Processor 300 operates to executeprocessor-executable steps, contained in program instructions describedbelow, so as to control the payment system computer 210 to providedesired functionality.

Communication device 301 may be used to facilitate communication with,for example, other devices (such as access points 208, 214, acquirerhost computer 206 and issuer host computer 212).

Input device 306 may comprise one or more of any type of peripheraldevice typically used to input data into a computer. For example, theinput device 306 may include a keyboard and a mouse. Output device 308may comprise, for example, a display and/or a printer.

Storage device 304 may comprise any appropriate information storagedevice, including combinations of magnetic storage devices (e.g.,magnetic tape and hard disk drives), optical storage devices such as CDsand/or DVDs, and/or semiconductor memory devices such as Random AccessMemory (RAM) devices and Read Only Memory (ROM) devices, as well asso-called flash memory.

Storage device 304 stores one or more programs for controlling processor300. The programs comprise program instructions that containprocessor-executable process steps of payment system computer 210,including, in some cases, process steps that constitute processesprovided in accordance with principles of the present invention, asdescribed in more detail below.

The programs may include a database management application 310 thatallows the payment system computer 210 to generate, maintain, update andquery certain databases that are described below. The programs may alsoinclude an application program 312 for processing authorization requestssent to the payment system computer 210 from acquirer host computers. Aswill be seen, in a larger sense, the process of handling authorizationrequests also entails processing authorization responses sent to thepayment system computer 210 by issuer host computers in response toauthorization requests.

Storage device 304 may also store an account mapping database 314. Theaccount mapping database 314 may store a record for each issuedproximity-device-only account number to indicate which PAN theproximity-device-only account number is associated with. In a processthat is described below, the account mapping database 314 allows thepayment system computer 210 to map proximity-device-only account numbersto their corresponding PANs so that the proximity-device-only accountnumbers can be replaced with PANs before passing authorization requestson to the issuer financial institution.

Storage device 304 may also store an issuer database 316. The issuerdatabase 316 may map the BIN portion of PANs to the relevant datacommunication address information so that authorization requests can beproperly routed to the issuer financial institutions.

Further, storage device 304 may store a transaction database 318. Thetransaction database 318 may be used to keep records of the transactionsprocessed by the payment system computer 210. In some embodiments, thetransaction database 318 may be constituted by, or may be regularlyflushed to, a data warehouse that is maintained on a separate computer(not shown). The transaction data in the database 318 may be used, forexample, for post audit purposes or as required in connection withsubsequent clearing of the transactions.

The storage device 304 may also include a key database 322. The keydatabase 322 may store information used (as described below) in checkinga cryptographic security code generated for each transaction by theproximity device.

The storage device 304 may store additional software programs which arenot indicated in the drawing, but which may include one or moreoperating systems, device drivers, etc.

The payment system computer 210 may further include a hardware securitymodule 320 (indicated in phantom) which may be in communication with theprocessor 300. The hardware security module 320 may be provided toenhance the security of certain processes (discussed below) whereby thepayment system computer 210 confirms the validity of security codes thatmay be included in authorization requests received from acquirer hostcomputers.

FIG. 4 is a flow chart that illustrates a process that may be performedby the payment system computer 210 in accordance with aspects of thepresent invention.

At 402 in FIG. 4, the process, or a particular processing thread, idlesuntil an authorization request is received from the acquirer hostcomputer 206. Once an authorization request has been received,processing advances to decision block 404. At decision block 404, thepayment system computer 210, and particularly processor 300 (FIG. 3),parses the authorization request to determine the account number thatwas submitted in connection with the purchase transaction that is thesubject of the authorization request. Further, in decision block 404,the payment system computer 210 determines from the BIN portion of theaccount number whether the account number is from a range of accountnumbers that have been set aside for proximity-device-only accountnumbers that are eligible for mapping. If not, then the authorizationrequest is forwarded on, in normal fashion, to the issuer of the accountidentified by the account number, as indicated at 406 in FIG. 4.

However, if a positive determination is made at 404 (i.e., if theaccount number in the authorization request is in a range of accountnumbers reserved for proximity-device-only account numbers that areeligible for mapping), then decision block 408 follows decision block404. At decision block 408, the payment system computer 210 determineswhether the authorization request indicates that the purchasetransaction was initiated by proximity-reading a proximity paymentdevice. If a negative determination is made 408 (i.e., the purchasetransaction is based on a mag stripe read, an internet basedtransaction, or another sort of transaction other than proximity-readinga proximity payment device), then it is likely that the transaction isfraudulent, since, by the process logic, it had previously beendetermined that the account number was from a range of account numbersreserved for proximity-device-only account numbers. Accordingly,following a negative determination at 408, the payment system computer210 sends a message (as indicated at 410 in FIG. 4) to the acquirer hostcomputer 206 to indicate that the authorization request is declined. (Aswill be appreciated, the “declined” message would then be passed on tothe POS terminal 204—or other merchant device that originated theauthorization request—by the acquirer host computer 206.)

However, if a positive determination is made at 408 (i.e., thetransaction is of the proper—proximity-read—type), then the paymentsystem computer 210 performs another check, as indicated at decisionblock 412. In particular, at decision block 412 the payment systemcomputer 210 determines whether the account number included in theauthorization request is listed as currently active. This check may beperformed by a reference to a suitable database, which may be theaccount mapping database 314 shown in FIG. 3.

If it is determined at decision block 412 that the account number is notactive, then (step 410) the payment system computer 210 sends a messageto the acquirer host computer 206 that the authorization request isdeclined. (As mentioned above, the “declined” response would then bepassed from the acquirer host computer 206 to the POS terminal 204.)

However, if at 412 the account number is determined to be active, thenthe process of FIG. 4 may advance to another check, which is indicatedat decision block 414. At decision block 414, the payment systemcomputer 210 may check the validity of a security code that was includedin the authorization request. In some embodiments, the security code maybe a static value that is always read from the proximity payment devicefor each transaction. More preferably, however, the security code may bedynamic, as is the case with the so-called “dynamic CVC3” security codecalled for by the PayPass standard for proximity payment devices. Adescription of the dynamic CVC3 security code is contained in a paperentitled “PayPass Information Paper: ATC Regeneration and Tracking”(Version 1.4) published by MasterCard International Inc. on Oct. 26,2004, and hereby incorporated herein by reference. To briefly summarizecertain aspects of the dynamic CVC3 feature, the proximity paymentdevice 202 performs a cryptographic calculation to generate the dynamicCVC3 for the transaction based on the following inputs: (a) acryptographic key, (b) an “unpredictable number” generated for thetransaction by the POS terminal 204 and transmitted to the proximitypayment device 202 from the POS terminal 204 in connection with thetransaction, (c) a transaction count value maintained in the proximitypayment device to indicate how many transactions the proximity paymentdevice has been used for, and (d) certain static data stored in theproximity payment device.

In some embodiments of decision block 414, the payment system computer210 may attempt to reproduce the cryptographic calculation performed bythe proximity payment device 202 to determine whether the cryptographiccalculation as performed by the payment system computer 210 produces thesame result as the dynamic CVC3 security code generated by the proximitypayment device and included in the authorization request. The paymentsystem computer 210 may obtain the inputs (a) and (d) referred to abovefrom a database that is available to the payment system computer 210.For example, this information may be stored in the key database 322.Input (b)—the unpredictable number generated for the transaction by thePOS terminal 204—may be included with the authorization request. Thepayment system computer 210 may regenerate input (c)—the transactioncount value—from one or more low-order digits of the transaction countvalue included with the authorization request, by also using transactioncount information independently stored by the payment system computer210 for the proximity payment device in question.

If the security code check performed at 414 fails, then the paymentsystem computer 210 may send a message to decline the authorizationrequest to the acquirer host computer 206, as indicated at 410. However,if the security code is found at 414 to be valid, then step 416 mayfollow 414. At 416, the payment system computer 210 may access theaccount mapping database 314 to translate the proximity-device-onlyaccount number included in the authorization request to the PAN withwhich the proximity-device-only account number is associated. Then, at406, the payment system computer 210 may route the authorization requestto the issuer host computer 212 with the PAN substituted for theproximity-device-only account number that was initially included in theauthorization request as received by the payment system computer 210from the acquirer host computer 206. It will be appreciated that theissuer host computer 212 may then determine whether to accept or declinethe authorization request (with the PAN included therein) in accordancewith conventional practices.

In some embodiments, the authorization request, as sent from the paymentsystem computer 210 to the issuer host computer, may include anauxiliary data section containing the proximity-device-only accountnumber initially included in the authorization request as received bythe payment system computer 210. This may be done for convenience ofreference in later processing, but the proximity-device-only accountnumber most likely would not be used by the issuer host computer 212 forthe purpose of accessing the customer's account to determine whether theauthorization request should be approved.

Although this is not explicitly indicated in FIG. 4, in someembodiments, when the payment system computer 210 passes theauthorization request to the issuer host computer 212, the paymentsystem computer 210 may include an indication as to whether the securitycode was found to be valid (cf. step 1006, discussed below in connectionwith FIG. 10).

Whether the issuer host computer 212 determines that the authorizationrequest should be approved or declined, in either case the issuer hostcomputer 212 would transmit an authorization response back to thepayment system computer 210. FIG. 5 is a flow chart that illustrates aprocess that may be performed by the payment system computer 210 inhandling the authorization response received from the issuer hostcomputer 212.

At 502 in FIG. 5, the process, or a particular processing thread, idlesuntil the authorization response is received from the issuer hostcomputer 212. Once the authorization response has been received,processing advances to decision block 504. At decision block 504, thepayment system computer 210, and particularly processor 300 (FIG. 3),determines whether the authorization response requires that the PANincluded in the authorization response be translated back to theproximity-device-only account number that was included in theauthorization request. That is, the payment system computer 210determines whether the authorization response is responding to anauthorization request for which the payment system computer 210performed proximity-device-only account number to PAN mapping. Thepayment system computer 210 may make this determination, for example,based on a code or flag in the authorization response. Alternatively,the payment system computer 210 may make this determination by using atransaction reference number included in the authorization response toaccess a database (e.g., transaction database 318, FIG. 3) to look upinformation concerning the authorization request to determine whetherproximity-device-only account number to PAN mapping was performed by thepayment system computer 210 with reference to the authorization request.

If the payment system computer 210 determines at 504 that PAN toproximity-device-only account number mapping is needed, then it proceedswith the mapping, as indicated by block 506 in FIG. 5. That is, thepayment system computer 210 may access the account mapping database314—additionally or alternatively, the payment system computer 210 mayaccess the transaction database 318—for the purpose of determining theproximity-device-only account number to be substituted for the PANincluded in the authorization response received from the issuer hostcomputer 212. For example, if it is the case that more than oneproximity payment device has been issued for a given payment cardaccount, such that more than one proximity-device-only account number isassociated with the PAN which identifies the payment card account, thenthe transaction database 318 may be the sole available source ofinformation concerning which of the associated proximity-device-onlyaccount numbers was included in the authorization request received fromthe acquirer host computer 206. The reference to the transactiondatabase 318 may be based on a transaction reference number included bythe issuer host computer 212 in the authorization response; the sametransaction reference number may have been previously included in theauthorization request as sent to the issuer host computer 212 by thepayment system computer 210.

Step 508 follows step 506 in the process of FIG. 5. At step 508, thepayment system computer 210 routes the authorization response to theacquirer host computer 206 with the proximity-device-only account numberthat was obtained at 506 inserted in the authorization response in placeof the PAN that was in the authorization response as it was received bythe payment system computer 210 from the issuer host computer 212. Insome embodiments, the authorization response, as sent from the paymentsystem computer 210 to the acquirer host computer 206, may include anauxiliary data section that contains the PAN that was included in theauthorization response as received by the payment system computer 210from the issuer host computer 212.

It will be appreciated that the acquirer host computer 206 will forwardthe authorization response on to the POS terminal 204, and in accordancewith conventional practices the purchase transaction at the POS terminal204 will be completed or aborted, depending on whether the authorizationresponse indicates that the authorization request was approved ordeclined. It will also be appreciated that when the process of FIG. 4terminates in step 410 (“decline” message sent to acquirer hostcomputer), in such cases the acquirer host computer 206 will pass the“decline” message to the POS terminal 204, causing the purchasetransaction to be aborted.

In some embodiments of the process of FIG. 4, the payment systemcomputer 210 forwards the authorization request to the issuer hostcomputer 212 even if the security code was not found to be valid. If theprocess of FIG. 4 is so embodied, then the process of FIG. 5 may includesteps (not shown) in which the payment system computer 210 refers to thetransaction database 318 to determine whether the security code includedin the authorization request did not check out, and if so the paymentsystem computer 210 may insert an error message to that effect in theauthentication response before forwarding the authentication response tothe acquirer host computer 206. It may also be the case in the processof FIG. 4 that, if the security code in the authorization request doesnot check out, the payment system computer 210 includes an indication tothat effect in the authorization request as forwarded from the paymentsystem computer 210 to the issuer host computer 212.

In some embodiments, transactions for which the authorization requestsare approved may subsequently be cleared (e.g., in a batch mode) betweenthe issuer and acquirer banks The clearing function may be performed bythe payment card association. In particular, the payment cardassociation may operate one or more computers (not shown), in additionto the payment system computer depicted in FIGS. 2 and 3, for thepurpose of performing clearing functions among the member banks of thepayment card association. In accordance with aspects of the presentinvention, when a payment card association clearing computer (not shown)receives a clearing message from an issuer bank that contains aproximity-device-only account number, the payment card associationclearing computer translates the proximity-device-only account numberinto the PAN with which the proximity-device-only account number isassociated. Moreover, when appropriate to the particular transaction,the payment card association clearing computer translates PANs, receivedin clearing messages from issuer banks, into associatedproximity-device-only account numbers.

In some embodiments, transaction data stored by the payment cardassociation (e.g., in a “data warehouse”) will include, when appropriatefor particular transactions, both the PAN and the proximity-device-onlyaccount number. This may aid in subsequent inquiries about transactions.

In some embodiments, to increase convenience of operation for paymentcard account issuers, the payment card association, or another party,may take responsibility for issuing proximity payment devices and forassociating the corresponding proximity-device-only account numbers withthe appropriate PANs. FIG. 6 is a block diagram which illustrates asystem 600 which handles at least some aspects of issuance of proximitypayment card devices.

The system 600 shown in FIG. 6 includes a server computer 602 whichhosts a website which allows payment card account holders to request andregister for proximity payment devices. As noted above, the proximitypayment device registration server computer 602 may be operated by apayment card association. The system 600 also includes numerous usercomputers 604 (e.g., conventional personal computers) that are in datacommunication on occasion with the proximity payment device registrationserver computer 602 via a data network 606 (e.g., the Internet). Theuser computers 604 may be operated from time to time by payment cardaccount holders to initiate a registration procedure for a proximitypayment device, as described below.

Although not shown in FIG. 6, a data communication network may connectthe server computer 602 with the payment system computer 210 shown inFIGS. 2 and 3 and/or with the account mapping database 314 shown in FIG.3.

FIG. 7 is a block diagram representation of an example embodiment of theproximity payment device registration server computer 602. In itshardware aspects, the proximity payment device registration servercomputer 602 may be conventional, and similar to the hardware componentsdescribed above in connection with the payment system computer 210. Thehardware aspects of the proximity payment device registration servercomputer 602 will therefore not be further described, except to mentionthat the proximity payment device registration server computer 602 mayinclude a processor 700 in communication with a communication device701, a storage device 704, an input device 706, and an output device708.

The storage device 704 may store the following application programsand/or program modules: (a) a program/module 710 to handle registrationtransactions initiated by payment card account holders; (b) aprogram/module 712 to assign proximity-device-only account numbers toproximity payment devices requested by payment card account holders inthe registration transactions; (c) a program/module 714 to initiateactions required to supply proximity payment devices in response to therequests therefor by the payment card account holders; and (d) aprogram/module 716 to handle updating of an account number database(such as database 314) to reflect association of proximity-device-onlyaccount numbers with PANs as a result of fulfillment of requests forproximity payment devices.

Continuing to refer to FIG. 7, the storage device 704 may also store adatabase 718 of records for payment card accounts which were issued bythe issuing financial institution in question and which are eligible forrequests for proximity payment devices. The account database 718 may beindexed by the PANs for the payment card accounts, and the record foreach account may also include information about the account holders,such as names and addresses.

The storage device 704 may store additional data and programs beyondthose explicitly mentioned above. For example, the storage device 704may store conventional programs such as one or more operating systems,web hosting software programs, database management programs, devicedrivers, etc.

FIG. 8 is a flow chart that illustrates a process that may be performedby the proximity payment device registration server computer 602 inaccordance with aspects of the present invention.

The process of FIG. 8 begins at 802 with a payment card account holdervisiting the website hosted by the proximity payment device registrationserver computer 602. The payment card account holder may have initiatedthe website visit by operating his/her user computer 604 in aconventional manner. The payment card account holder may have chosen tovisit the website hosted by the proximity payment device registrationserver computer 602 in response to activities undertaken by the issuingfinancial institution (and/or by the payment card association) topromote dissemination of proximity payment devices. For example, thepayment card account holder may have received promotional literatureabout the availability of proximity payment devices, and the existenceof and web address for the registration website, in a monthly paymentcard account statement that the payment card account holder receivedfrom the issuer. Alternatively, the payment card account holder may havenavigated to the website hosted by the proximity payment deviceregistration server computer 602 from a link provided on an onlinebanking website or other website operated by or on behalf of the issuer.

The website hosted by the proximity payment device registration servercomputer 602 may preferably include a logo or logos associated with theissuer or other branding information related to the issuer, so that thepayment card account holder may associate the website with the issuernotwithstanding that the website may be operated for the issuer by thepayment card association or by another party. Thus, briefly referringagain to FIG. 6, there may be a considerable number of proximity paymentdevice registration server computers 602 in the system 600, and/or theproximity payment device registration server computer 602 may host aconsiderable number of proximity payment device registration websites,such that a separate proximity payment device registration website maybe provided for each issuer which desires proximity payment devices tobe made available to its payment card account holders.

Referring again to FIG. 8, once the payment card account holder hascommenced a visit to the website hosted by the proximity payment deviceregistration server computer 602, the proximity payment deviceregistration server computer 602 may prompt the payment card accountholder to enter information for setting up the payment card accountholder's account on the website, as indicated by block 804 in FIG. 8.The setup information may include, for example, a username, a PIN(personal identification number) or password for website purposes, andone or more security information questions (e.g., mother's maiden name,last 5 digits of social security number, etc.)., as indicated by block.

Further, as indicated by block 806, the proximity payment deviceregistration server computer 602 may prompt the payment card accountholder to enter personal information such as the payment card accountholder's day and month of birth. Next, at block 808, proximity paymentdevice registration server computer 602 may prompt the payment cardaccount holder to enter the PAN that identifies his/her payment cardaccount with the issuer. Presumably, the payment card account holder isable to enter this information by referring to his/her payment card (magstripe card) previously issued to the payment card account holder by theissuer.

In the next block, 810, the proximity payment device registration servercomputer 602 may prompt the payment card account holder to enter his/herbilling address, and the proximity payment device registration servercomputer 602 may verify the billing address of the payment card accountholder by using the PAN entered at block 808 to reference the accountdatabase 718 (FIG. 7).

Continuing to refer to FIG. 8, at 812 the proximity payment deviceregistration server computer 602 may prompt the payment card accountholder to enter the security code from the back of his/her payment card,and the proximity payment device registration server computer 602 maythen verify the security code entered by the payment card account holderby, e.g., sending a message to the issuer to request verification of thesecurity code.

At 814, the proximity payment device registration server computer 602may prompt the payment card account holder to indicate how manyproximity payment devices he/she wishes to receive and/or to select thetype or types (e.g., keyfob, wristband and/or combined proximity paymentdevice/mag strip card) of proximity payment device that the payment cardaccount holder wishes to receive.

At 816 the proximity payment device registration server computer 602generates and assigns the required number of proximity-device-onlyaccount numbers to the payment card account holder from a range of suchaccount numbers that has previously been established by or for theissuer. Next, at 818, the proximity payment device registration servercomputer 602 issues one or more orders to a supplier or suppliers ofproximity payment devices to load the proximity-device-only accountnumber(s) assigned at 816 into the proximity payment device(s) selectedby the payment card account holder at 814. The supplier(s) is (are) alsoinstructed to fulfill the payment card account holder's request bymailing the proximity payment device(s) to the payment card accountholder's home address.

In accordance with conventional practices, the package mailed to thepayment card account holder instructs the payment card account holder toconfirm receipt of the proximity payment device(s) so as to activate theassigned proximity-device-only account numbers. In accordance withaspects of the present invention, the instructions direct the paymentcard account holder to again visit the website hosted by the proximitypayment device registration server computer 602. Thus, the process ofFIG. 8 includes a decision block 820 at which the proximity paymentdevice registration server computer 602 determines whether the paymentcard account holder has visited the website to confirm receipt of theproximity payment device(s). (Alternatively to confirming receipt byvisiting the website, the instructions may direct or allow the user toconfirm receipt via an interactive telephone voice response system.)

Once the proximity payment device registration server computer 602determines at 820 that the payment card account holder has confirmedreceipt of the proximity payment device(s), then the process of FIG. 8advances to steps 822, 824 and 826. At step 822, the proximity paymentdevice registration server computer 602 activates theproximity-device-only account number(s) assigned at step 816. At step824 the proximity payment device registration server computer 602 causesthe account mapping database 314 (FIG. 3) to be updated so that thenow-activated proximity-device-only account number(s) is (are)associated with the payment card account holder's PAN. At step 826, theproximity payment device registration server computer 602 confirms tothe payment card account holder that the proximity payment device(s) has(have) been activated.

In some embodiments, although not indicated in FIG. 8, the servercomputer 602 may also be accessed by account holders to report lost orstolen proximity payment devices. When the server computer 602 receivessuch reports, it may cause the appropriate database(s) to be updated sothat the proximity-device-only account number in question is no longerlisted as “active”.

Reference is now made once again to the payment card transactionprocessing system 200 depicted in FIG. 2. In some alternativeembodiments of the invention, the payment system computer (designated asblock 210 in FIG. 2) may lack some of the capabilities that weredescribed above. For example, the payment system computer may lack thecapabilities for mapping proximity-device-only account numbers to PANs.In such cases, the account number mapping may be performed by the issuerhost computer 212, or the entire scheme of proximity-device-only accountnumbers may not be implemented, and instead the account numbers storedin the proximity payment device RFID chips may be the same as the PANfor the relevant account, or may be handled in a similar manner to aPAN.

FIG. 9 is a block diagram representation of an alternative embodiment ofthe payment system computer seen in FIG. 2, lacking some of the softwareprograms and/or database(s) of the previously described embodiments, anddesignated generally by reference numeral 210 a in FIG. 9.

As seen from FIG. 9 the payment system computer embodiment depictedtherein may have all of the hardware components described above inrelation to the payment system computer embodiment depicted in FIG. 3.Moreover, the software programs and databases stored in the storagedevice 304 in the payment system computer 210 a may generally be asubset of the programs and databases of the embodiment depicted in FIG.3. In particular, among other data, the storage device 304 may store thekey database 322 referred to above. Also, the authorization requesthandling application program (indicated by reference numeral 312 a inFIG. 9), may operate somewhat differently from the operation of theembodiment of FIG. 3, as described above in connection with FIGS. 4 and5. Operation of the authorization request handling application program312 a as performed in the payment system computer 210 a is describedimmediately below in conjunction with FIG. 10.

FIG. 10, then, is a flow chart that illustrates a process performed bythe payment system computer 210 a in accordance with aspects of thepresent invention.

At 1002 in FIG. 10, the process, or a particular processing thread,idles until an authorization request is received from the acquirer hostcomputer 206. Once an authorization request has been received,processing advances to decision block 1003. At decision block 1003, itis determined whether the account number included in the authorizationrequest falls within a range of account numbers that is eligible for thepayment system computer 210 a to perform a security code check. (Thisstep may also involve checking the expiration date for the accountnumber.) If the account number is not eligible for security codechecking, the process loops back to 1002. But if the account number iseligible for security code checking, then the process advances to block1004. At block 1004, the payment system computer 210 a may check thevalidity of a security code that was included in the authorizationrequest. The security code may be of one of the types describedhereinabove in connection with block 414. Also the procedure used tocheck the security code may be in accordance with the above descriptionof block 414. To be more explicit, the security code may be like theabove-referenced “dynamic CVC3” and the procedure for checking thesecurity code may include the known cryptographically based techniquereferred to hereinabove.

Continuing to refer to FIG. 10, block 1006 follows block 1004. At block1006, the payment system computer 210 a forwards the authorizationrequest to the issuer host computer 212. As forwarded to the issuer hostcomputer 212 by the payment system computer 210 a, the authorizationrequest may include an indication as to whether or not the security codewas found to be valid by the payment system computer 210 a. Thatindication may have been inserted in the authorization request by thepayment system computer 210 a.

Following block 1006 in FIG. 10 is a decision block 1008. At 1008, theprocess, or a particular processing thread, idles until theauthorization response is received from the issuer host computer 212.Once the authorization response has been received, processing advancesfrom 1008 to decision block 1010. At decision block 1010, the paymentsystem computer 210 a determines whether it is necessary to insert anerror message in the authorization response to the effect that thesecurity code included in the authorization request was not found to bevalid. In other words, the payment system computer 210 a may determineat 1010 whether the security code included in the authorization requestwas found at 1004 to be invalid. In some embodiments, the payment systemcomputer 210 a may make this determination by referring to dataconcerning the transaction that was stored in transaction database 318.Alternatively, the payment system computer 210 may make thedetermination based on an indication in the authorization response asreceived from the issuer host computer 212. That is, the authorizationresponse as received from the issuer host computer 212 may reflect theresult of the security code check, as indicated in the authorizationrequest as sent from the payment system computer 210 a to the issuerhost computer 212.

If a positive determination is made at 1010 (i.e., if the payment systemcomputer 210 a determines that it is necessary to insert an errormessage), then, as indicated at 1012, the payment system computer 210 ainserts into the authorization response the error message to indicateinvalidity of the security code.

Step 1014 follows step 1012. At step 1014, the payment system computer210 a routes the authorization response to the acquirer host computer206 with the error message present in the authorization response.Alternatively, if a negative determination is made at 1012, then step1014 may directly follow 1010, such that the payment system computer 210a routes the authorization response to the acquirer host computer 206without the error message being included in the authorization response.

In an alternative embodiment of the process of FIG. 10, the paymentsystem computer 210 a declines transactions that fail the security codecheck without forwarding them to the issuer; in this embodiment thepayment system computer 210 a only forwards to the issuer transactionsthat pass the security code check, and sends an advice message to theissuer with respect to each declined transaction.

FIG. 11 is similar to FIG. 2, and again represents the payment cardtransaction processing system 200 while also schematically representinga circumstance when the issuer host computer 212 is not available tohandle transactions, as indicated by the “X” mark 1102. Such a situationis known to those who are skilled in the art, and it is further knownthat in such a situation, the payment system computer 210 may beprogrammed to “stand in” for the issuer host computer 212 by handlingauthorization requests in accordance with rules that the issuer hasestablished. In accordance with aspects of the present invention, thepayment system computer 210 a (FIG. 9) is present in the payment cardtransaction processing system and “stands in” for the issuer hostcomputer 212 when necessary, while also providing functions relative tochecking the validity of security codes included in the authorizationrequests.

FIG. 12 is a flow chart that illustrates a process that may be performedin accordance with aspects of the invention by the payment systemcomputer 210 a, and FIG. 13 is a flow chart that illustrates certaindetails of the process of FIG. 12.

The process of FIG. 12 (or a particular processing thread) idles at 1202until an authorization request is received from the acquirer hostcomputer 206. Once an authorization request has been received,processing advances to decision block 1204. At decision block 1204, thepayment system computer 210 a determines whether the issuer hostcomputer 212 (i.e., the particular issuer that issued the payment cardaccount to be accessed by the authorization request) is available tohandle transactions. (As is known, issuer host computers mayoccasionally be unavailable because of scheduled maintenance,installations of replacement hardware or software, or for otherreasons.) If the payment system computer 210 a determines at 1204 thatthe relevant issuer host computer 212 is available, then the paymentsystem computer 210 a proceeds, as indicated at 1206, to handle theauthorization request in a normal fashion (e.g., as illustrated in FIG.10).

If the payment system computer 210 a determines at 1204 that therelevant issuer host computer 212 is not available, then block 1208follows decision block 1204. In block 1208 the payment system computer210 a enters and operates in a “stand in” processing mode. Details ofthe stand in processing mode are illustrated in FIG. 13.

Referring, then, to FIG. 13, at 1302, the payment system computer 210 amay check the validity of a security code that was included in theauthorization request if, by prior arrangement with the issuer, theissuer had requested that the payment system computer do so. Thesecurity code may be of one of the types described hereinabove inconnection with block 414. (This step may also entail checking theexpiration date for the account number.) Also the procedure used tocheck the security code may be in accordance with the above descriptionof block 414. To be more explicit, the security code may be like theabove-referenced “dynamic CVC3” and the procedure for checking thesecurity code may include the known cryptographically based techniquereferred to hereinabove.

Continuing to refer to FIG. 13, a decision block 1304 follows 1302. At1304, the payment system computer 210 a determines whether the securitycode check performed at 1302 indicated that the security code was valid.If not, block 1306 follows decision block 1304. At 1306, the paymentsystem computer 210 a transmits an authorization response to theacquirer host computer 206 with an indication that the authorizationrequest is declined. Next, at 1308, the payment system computer 210 atransmits to the issuer host computer 212 (or stores for latertransmission to the issuer host computer 212) an authorization advicemessage to indicate (a) that the payment system computer 210 a receivedthe authorization request, (b) that the payment system computer 210 adeclined the authorization request, and (c) that the security codefailed the check.

Referring again to decision block 1304, if it is determined that thesecurity code is valid, then block 1310 follows 1304. At 1310, thepayment system computer 210 a performs tests on the transaction such asare conventionally performed in the ‘stand in’ role.

Decision block 1312 follows 1310. At decision block 1312, the paymentsystem computer 210 a determines, based on results of the testsperformed at 1310, whether the authorization request should be accepted.If so, then block 1314 follows 1312. At 1314, the payment systemcomputer 210 a transmits an authorization response to the acquirer hostcomputer 206 with an indication that the authorization request isapproved. Block 1316 then follows, at which the payment system computer210 a transmits to the issuer host computer 212 (or stores for latertransmission to the issuer host computer 212) an authorization advicemessage to indicate (a) that the payment system computer 210 a receivedthe authorization request, and (b) how the payment system computer 210 aresponded on the issuer's behalf.

Referring again to decision block 1312, if a negative determination ismade (i.e., if the tests indicate that the authorization request shouldbe declined), then block 1318 follows 1312. At 1318, the payment systemcomputer 210 a transmits an authorization response to the acquirer hostcomputer 206 with an indication that the authorization request isdeclined. Block 1316 then follows, at which the payment system computer210 a transmits to the issuer host computer 212 (or stores for latertransmission to the issuer host computer 212) an authorization advicemessage to indicate (a) that the payment system computer 210 a receivedthe authorization request, and (b) how the payment system computer 210 aresponded on the issuer's behalf.

In the embodiment depicted in FIGS. 4 and 5, the payment system computerchecks as to whether the transaction is a proximity-read transaction,and translates the proximity-device-only account number to the PAN withwhich the proximity-device-only account number is associated. However,in other embodiments, these functions may be performed by the issuerhost computer.

In some embodiments, the payment system computer 210 may receive anauthorization request and perform the function of mapping aproximity-device-only account number to a PAN, and may perform thecryptographic security code check as described above in connection withFIG. 4, and then may determine that the issuer host computer 212 is notavailable. At that point, the payment system computer 210 may enter a‘stand in’ mode of operation, like that of FIG. 13, and may use theresult of the security code check in deciding whether to approve ordecline the authorization request on behalf of the issuer.

Whenever, in the above description or in the appended claims, referenceis made to transmitting a message to an issuer host computer, it shouldbe understood that this includes transmitting a message to a computeroperated by a service provider on behalf of the issuer. Similarly,receiving a message from an issuer host computer includes receiving amessage from a computer operated by a service provider on behalf of theissuer. Further, transmitting a message to an acquirer host computerincludes transmitting a message to a computer operated by a serviceprovider on behalf of the acquirer, and receiving a message from anacquirer host computer includes receiving a message from a computeroperated by a service provider on behalf of the acquirer.

As used herein and in the appended claims, “proximity reading” refers toan activity, engaged in by a proximity reader that is part of orassociated with a point of sale terminal or similar device, in which theproximity reader receives an account number from a proximity paymentdevice by wireless communication.

Among other possible alternative embodiments of the invention, theprocess illustrated in FIG. 4 could be modified by omitting at leastsome of the checks indicated in FIG. 4, although it is preferable thatthe check indicated at 408 not be omitted. In some embodiments, theorder in which the checks are performed may be different from the orderindicated in FIG. 4.

The flow charts and descriptions thereof herein should not be understoodto prescribe a fixed order of performing the method steps describedtherein. Rather, the method steps may be performed in any order that ispracticable.

As used herein and in the appended claims, the term “payment cardaccount” includes a credit card account or a deposit account that theaccount holder may access using a debit card. The term “payment cardaccount number” includes a number that identifies a payment card accountor a number carried by a payment card, or a number that is used to routea transaction in a payment system that handles debit card and/or creditcard transactions. The term “payment card” includes a credit card or adebit card.

Although the present invention has been described in connection withspecific exemplary embodiments, it should be understood that variouschanges, substitutions, and alterations apparent to those skilled in theart can be made to the disclosed embodiments without departing from thespirit and scope of the invention as set forth in the appended claims.

1. A method comprising: receiving, by a payment system computer, anauthorization request for a purchase transaction; determining, by thepayment system computer, that the authorization request arose fromproximity-reading a proximity payment device; determining that a firstaccount number in the authorization request is qualified for mapping;mapping the first account number included in the authorization requestinto a second account number associated with the first account;transmitting the authorization request to an issuer financialinstitution with the second account number substituted for the firstaccount number in the authorization request; receiving, by the paymentsystem computer, an authorization response from the issuer financialinstitution, said authorization response including said second accountnumber; mapping the second account number to the first account number;and transmitting the authorization response to an acquirer financialinstitution with the first account number substituted for the secondaccount number in the authorization response.
 2. The method of claim 1,further comprising: including the second account number as auxiliarydata in the authorization response transmitted to the acquirer financialinstitution.
 3. The method of claim 1, wherein the second account numberis a primary account number that identifies a payment card account. 4.The method of claim 3, wherein: said proximity payment device isassociated with said payment card account; and said first account numberis assigned to said proximity payment device.
 5. The method of claim 1,further comprising: including the first account number as auxiliary datain the authorization request transmitted to the issuer financialinstitution.
 6. A system comprising a storage device and a processor,wherein the storage device storing instructions configured to cause theprocessor to: receive an authorization request for a purchasetransaction; determine that the authorization request arose fromproximity-reading a proximity payment device; determine that a firstaccount number in the authorization request is qualified for mapping;map the first account number included in the authorization request intoa second account number associated with the first account; transmit theauthorization request to an issuer financial institution with the secondaccount number substituted for the first account number in theauthorization request; receive an authorization response from the issuerfinancial institution, said authorization response including said secondaccount number; map the second account number to the first accountnumber; and transmit the authorization response to an acquirer financialinstitution with the first account number substituted for the secondaccount number in the authorization response.
 7. The storage devicesystem of claim 6, further comprising instructions configured to causethe processor to transmit the second account number as auxiliary data inthe authorization response transmitted to the acquirer financialinstitution.
 8. The system of claim 6, wherein the second account numbertransmitted to an issuer financial institution is a primary accountnumber that identifies a payment card account.
 9. The system of claim 8,wherein the proximity payment device is associated with the payment cardaccount, and wherein the first account number is assigned to saidproximity payment device.
 10. The system of claim 6, further comprisinginstructions configured to cause the processor to transmit the firstaccount number as auxiliary data in the authorization requesttransmitted to the issuer financial institution.